Is it okay to purchase airline and hotel tickets for a trip during this week, this weekend, next Monday or Wed? Or can purchasing tickets for a trip bring some bad kharma to the trip? What about dry cleaning clothes, opening new bank accounts, and transferring or rolling over funds to new bank accounts or funds?
Regarding the airline tickets, if you have to buy them now, or you will incur a loss , then it is permitted. Otherwise it preferably should wait. It is the same with the bank accounts. Dry cleaning should wait until after chatzos on Wednesday, which is the 10th of Av. However business activities may be done right after T’ bav.
Chut Shani Shabbos 2 pg. 328.